Worldview:

In 1938, in the border region between Germany and Poland, an ancient underground aquifer was breached during deep mining for war resources. A mutant parasite, dormant since before the Ice Age, was released into the world.

Infection Routes:

Oral Infection:

Larvae penetrate the digestive system through contaminated drinking water or by eating plants and animals that have consumed it.

Injection Infection:

Being pierced by an infected individual's tentacle allows eggs to be injected into the body through an ovipositor inside the tentacle.

Penetration Infection:

Adult parasites burrow directly through the skin.

Infection Symptoms:

Early Stage:

Extreme thirst, binge eating, sensation of a foreign body under the skin.

Mid Stage:

Loss of speech, dark blue veins (migration paths) protruding on the skin.

Late Stage:

Divided into three major types:

Common Type: Reason is extinguished. Adult tentacles protrude from the eyes or mouth. They form swarms, making clicking sounds with their teeth. Driven by spawning instincts, they obsess over water (rivers, sewers) and spray larvae by tearing open their own abdomens underwater.

Mutant Type: Occurs mainly in physically fit hosts. Bones and muscles are restructured. Tentacles burst from the abdomen, ribs protrude like blades, or limbs transform into weapons. Dozens of mutants may fuse to evolve into a wall of flesh.

Mimic Type: Instead of eating the brain, the parasite perfectly integrates with the host's nervous system. They are indistinguishable from humans in appearance and maintain speech and intelligence. They understand and can mimic human fear and bonds. They pretend to be survivors while secretly spawning in water or injecting eggs into other survivors.

Geopolitics:

Europe:

Poland, East Germany, and Eastern Europe have been erased from the map (Infected Zones). Britain, France, and Nazi remnants have established the 'Steel Wall' along the Rhine and declared a temporary truce. Stalin has ordered indiscriminate shelling of infected Soviet cities.

Asia:

Manchuria and the Korean Peninsula collapsed after Unit 731 failed to control their experiments. Chinese forces, independence armies, and Japanese forces either cooperate temporarily for survival or fend for themselves in the chaos.

USA:

Total isolationism. Full coastal blockade and indiscriminate sinking of approaching vessels. Internally, a feverish witch hunt to root out the infected.

Battlefield and Technology:

Weapons:

Guns: Bullets have lethality but lack stopping power and may be ineffective against Mutant Types. Fire: Parasites are extremely vulnerable to fire. Weapons using fire, such as Molotov cocktails or flamethrowers, are effective.

Society:

No cure exists. Upon infection, amputation of the infected limb or execution is the only response. Doctors are called 'Amputation Technicians.' On the radio, between jazz tracks, propaganda broadcasts repeatedly blare: "Suspect even your family, report them, burn them."